1. Field of the Invention
The present invention relates to a disk apparatus in which a plurality of types of disks having different diameters are loaded, and more particularly, to a disk apparatus in which both a large-diameter disk and a small-diameter disk can be reliably positioned with a simple structure.
2. Description of the Related Art
In disk apparatuses in which a disk is automatically loaded in order to play back information recorded on the disk or to record information on the disk, the loaded disk must be reliably positioned on a turntable in a rotating section. In disk apparatuses capable of loading two types of disks, that is, a small-diameter disk having a diameter of 8 cm and a large-diameter disk having a diameter of 12 cm, both the disks must be positioned.
For that purpose, some conventional disk apparatuses have, on the inner side, a positioning projection which the peripheral edge of a loaded disk abuts. The positioning projection is placed so that the peripheral edge of a small-diameter disk having a diameter of 8 cm abuts it. When a large-diameter disk having a diameter of 12 cm is loaded, the positioning projection is pressed by the large-diameter disk and abuts a stopper formed on the rear side. In this state, the large-diameter disk is positioned with its peripheral edge in contact with the positioning projection.
In the conventional disk apparatuses, when a small-diameter disk is loaded, the loading is detected and the positioning projection is locked in an initial position. When a large-diameter disk is loaded, the loading is detected and the positioning projection is unlocked so that it can move toward the inner side of the apparatus.
Therefore, a plurality of detecting means are necessary to detect whether or not the loaded disk is a small-diameter disk or a large-diameter disk, and a lock mechanism for locking the positioning projection also is necessary. This complicates the construction of the apparatus.
The present invention has been made to overcome the above problems, and an object of the present invention is to provide a disk apparatus of simplified structure in which both a large-diameter disk and a small-diameter disk can be positioned reliably.
According to one aspect, the present invention provides a disk apparatus wherein both a large-diameter disk and a small-diameter disk can be loaded in a chassis and are driven by a common rotating section. The disk apparatus includes a pair of detecting projections provided in a disk loading path and biased in a direction such as to move closer to each other, the detecting projections being pressed by the peripheral edge of the disk so as to change the opposing distance therebetween, and a pair of positioning projections provided in the disk loading path and placed offset from the detecting projections toward the inner side in the disk loading direction, the positioning projections being operated to change the opposing distance therebetween by the moving force of the detecting projections when the detecting projections are pressed by the peripheral edge of the disk. The chassis includes, in a top plate substantially parallel to the surface of a loaded disk, a pair of selection grooves corresponding to the positioning projections, each of the selection grooves including a first guide groove and a second guide groove disposed offset from the first guide groove toward the inner side in the disk loading direction. The selection grooves are shaped so that the positioning projections operate inside the first grooves when the opposing distance between the detecting projections is increased by the small-diameter disk, and so that the positioning projections move out of the first guide grooves and are pressed into the second guide grooves by the peripheral edge of the large-diameter disk when the opposing distance between the detecting projections is increased by the large-diameter disk. The small-diameter disk is positioned so that the center thereof can be placed in the rotating section by the positioning projections placed in the first guide grooves, and the large-diameter disk is positioned so that the center thereof is placed in the rotating section by the positioning projections placed in the second guide grooves.
In the disk apparatus of the present invention, the distance between the detecting projections varies depending on the diameter of the disk, and disks having different diameters are positioned by placing the positioning projections operated by the detecting projections in the first guide grooves and the second guide grooves. Therefore, a complicate detection means for detecting the diameter of the disk is unnecessary, and it is possible to reliably position both a large-diameter disk and a small-diameter disk on the rotating section with a simple structure.
Preferably, when the opposing distance between the detecting projections is increased, the positioning projections are moved closer to each other, the selection grooves are disposed on both sides of a moving line of the center of the disk, and the first guide grooves and the second guide grooves extend in a direction orthogonal to the moving line, and are connected adjacent to the moving line.
Preferably, the detecting projections are each provided at one end of each of a pair of detection arms, and the positioning projections are provided in a pair of positioning members connected to the respective other ends of the detection arms. The positioning projections can move in the selection grooves, and a large-diameter disk and a small-diameter disk abut the positioning projections and are positioned so that the centers thereof can be placed in the rotating section.
Further objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.